This paper describes a method for in vitro binding of auxins to particulate fractions from corn coleoptiles. The binding is auxin-specific: only auxins and auxin analogues that are known to interfere with auxin transport and/or growth specifically bind to the auxin receptors. Saturation kinetics show that the apparent KD values are between 1O~and 1O~M for auxin and auxin analogues. The particul...

Auxin(IAA)-induced extension growth of primary plant cell walls is regulated via cell wall loosening the molecular mechanism of which is unresolved. In electronmicroscopical studies it has been demonstrated that IAA-induced growth in grass coleoptiles is cbc ter ized by the IAA-induced occurrence of osmiophilic particles (OPs) specifically in the outer periplasmic space of the tension-stressed ...

Ethylene and abscisic acid (ABA) have a complicated interplay in many developmental processes. Their interaction in rice is largely unclear. Here, we characterized a rice ethylene-response mutant mhz4, which exhibited reduced ethylene-response in roots but enhanced ethylene-response in coleoptiles of etiolated seedlings. MHZ4 was identified through map-based cloning and encoded a chloroplast-lo...

Energy charge, adenine nucleotide levels, and protein synthesis were studied during the transfer of rice seedlings from air to anoxia. Within minutes, the energy charge value dropped from 0.90 in air to 0.50 in the seed and 0.60 in the coleoptile after the transfer to a nitrogen atmosphere, and then increased to a value of 0.80 during the subsequent hours. The sum of nucleotides also dropped to...

Excised apical segments of etiolated rice (Oryza sativa L.) coleoptiles produced ethylene. Increasing the number of cut sites per coleoptile increased the rate of ethylene formation. Ethylene produced by an etiolated-intact seedling in the dark was about a half of that by the excised coleoptile segment. Red light of low energy as well as of continuous irradiation inhibited the production of eth...

Phytochrome A (phyA) mRNA abundance decreased rapidly in total RNA samples isolated from 4-day-old etiolated oat seedlings following a red light pulse. Putative in vivo phyA mRNA degradation products were detectable both before and after red light treatment. Cordycepin-treated coleoptiles were unable to accumulate the chlorophyll alb-binding protein mRNA in response to red light, indicating tha...